Flywheel energy storage technology is an efficient mechanical energy storage technology which is a way to convert non-mechanical energy such as electrical energy, wind energy, and solar energy into kinetic energy of the flywheel. In recent years, since flywheel energy storage has the advantages of high energy density, high power density, and high energy conversion efficiency, at the same time, the flywheel energy storage is insensitive to temperature, friendly to the environment, and has longer service life, faster charging and discharging speed, and is easy for combination with other devices, so that the flywheel energy storage has obtained extensive research and application, especially has a good application prospects in the fields of system energy feedback and power regulations of a wind power generation system.
In order to reduce flywheel loss and improve energy storage efficiency of the flywheel, the flywheel is usually located in an airtight vacuum chamber. Therefore, in order to transfer the energy stored by the flywheel to a system, or transfer the mechanical energy of the system to the flywheel to be stored, a coupling device is required. The existing coupling device is designed to be a rotation shaft equipped with a rotary seal ring, and the rotation shaft can convert external energy into the kinetic energy of the flywheel. However, the rotary seal ring may inevitably produce gas leakage, with prolonged time of use, improvement of rotational speed, and increasing degree of aging, it would be far more likely to produce gas leakage for the rotary seal ring. Thus, in the existing flywheel energy storage device, an additional vacuum environment monitoring system is required to monitor working environment of the vacuum chamber and a vacuum holding system, thereof ensuring the flywheel work in a vacuum environment, which will result in increase the volume of the flywheel energy storage device and manufacturing cost.
A magnetic connector is used here to solve above-mentioned defects that the rotary seal ring can easily lead to gas leakage between physical contacts, the magnetic connector can omit the rotary seal ring and transfer the energy stored by the flywheel out of the vacuum chamber to the system without physical contact, or convert external energy into the kinetic energy of the flywheel to be stored without physical contact. Since the magnetic connector is used to the flywheel energy storage system, so that the rotary seal ring, the environment monitoring system and the vacuum holding system are omitted, thereof solving the defects of the existing rotary seal ring. However, an energy flow path of the flywheel energy storage device is very single, that is, the kinetic energy of the flywheel is transferred to rotating parts at low-speed side through rotating parts at high-speed side and a magnetic adjustment mechanism, or the mechanical energy at the low-speed side is transferred to a high-speed rotor in the vacuum chamber through the magnetic adjustment mechanism without contact, resulting in driving the flywheel accelerate, thus, the energy is stored in the flywheel. Thus, this flywheel energy storage device only has round-trip two single energy flow paths, which is not conducive to adjust the size of output-input power and flexibly configure energy. Moreover, the above mentioned flywheel energy storage device still has a larger size.